Despite adolescents’ suicidal thoughts and behaviors being major health problems, sparse literature exists on the roles of adolescents’ disclosing their feelings to caregivers in their suicidal thoughts and behaviors. This study examined whether adolescents’ comfort in disclosing their feelings and problems to caregivers predicts subsequent suicidal thoughts and behaviors and whether difficulties in emotion regulation mediate this association. High school students (N = 5,346 from 20 schools, 49% female-identified adolescents, and 35% 9th graders, 33% 10th graders, and 32% 11th graders) participated in the study for two years with four waves, each six months apart: fall semester in Year 1 (Wave 1), spring semester in Year 1 (Wave 2), fall semester in Year 2 (Wave 3), and spring semester in Year 2 (Wave 4). The degree to which adolescents felt comfortable disclosing their feelings and problems to caregivers at Wave 1 predicted lower suicidal thoughts and behaviors at Wave 4 directly and indirectly via higher emotional clarity at Wave 2 and feeling more able to handle negative emotions at Wave 3. Moreover, when female-identified adolescents reported feeling unable to handle negative emotions at Wave 3, they reported engaging in more suicidal thoughts and behaviors at Wave 4 than male-identified adolescents. Therefore, enhancing adolescents’ comfort in disclosing their feelings and problems to caregivers and adolescent emotion regulation and taking a nuanced approach to support female-identified adolescents regarding their ability to handle negative emotions could prevent adolescents’ suicidal thoughts and behaviors.